Jim Reaper wrote:
Sorry, forgot it might be a bit vague for a description...I believe its a
form of limestone. It's a tan brown and as far I could see there wasn't any
varnish/glaze over it and the surface is rough and not a polish finish.
The surface now looks dusty and very dull.

Limestone! Is it actually *in* Cornwall, or somewhere else? If it's in
Cornwall, and is made from stone from Cornwall, it'll be either slate
or granite. Cornish granite is a whitish rock with black speckles in
it. Slate could be most any sort of look, but your fire sounds like
"rustic slate". Do the individual stones exhibit any sort of "grain",
or layering? Is it uniform tan, or are there green bits?